PROJECT SUMMARY Perceptions that engaging in drinking behavior demarks the transition to university and exemplifies the experience of typical college students contribute to high rates of heavy alcohol consumption and alcohol- related problems among college students, compared to other populations. Perceived peer drinking norms are highly correlated with and predictive of self-reported drinking. This is especially concerning given that college students tend to overestimate how much alcohol their peers consume. Interventionists using the social norms approach seek to correct misperceptions of peer norms in order to reduce and prevent hazardous alcohol use among college students. Personalized normative feedback (PNF) involves presenting students with comparisons of their perceived norms, self-reported drinking, and the actual drinking rates of peers in order to highlight discrepancies between normative perceptions and actual peer norms. Intervention evaluation typically involves assessing whether treatment effects on alcohol use behaviors are attributable to changes in perceived norms. However, researchers have suggested additional mediators and moderators of intervention effects should be identified to further the current theoretical understanding of how the social norms approach operates to reduce alcohol use. Three distinct factors (i.e., individual differences in self-consciousness, information credibility, and proximity of the reference group) moderate the effects of norms and normative interventions on alcohol use, and may point to a previously unmeasured mechanism responsible for the effectiveness of PNF: cognitive dissonance. Dissonance, psychological discomfort that arises when confronted with two attitudes, behaviors, or beliefs that are incongruent, may be experienced when presented with normative information that is discrepant with one?s behavior or perceptions of peer behavior. The overall goal of the proposed research is to determine whether eliciting cognitive dissonance is a fundamental component of PNF in order to derive a complete understanding of the mechanisms responsible for intervention effects and improve the effectiveness of existing PNF interventions. To achieve this goal, a randomized-controlled trial using a 2 (PNF) X 2 (Cognitive Dissonance) experimental design will be conducted to assess intervention effects on college students? (N = 300) longitudinal alcohol use. The specific aims of this project are to: 1) determine if standard PNF effects on alcohol use are mediated and/or moderated by cognitive dissonance, and 2) assess whether increasing participants? dissonance experienced can enhance the effectiveness of PNF interventions. The impact of the proposed research is its ability to inform theory underlying the social norms approach, as well as provide valuable information regarding the design and evaluation of normative interventions. Further, this fellowship will provide valuable theoretical, methodological, and statistical training to aid the applicant?s development as an independent researcher.